Proper dispersion and distribution of curing agents in a rubber stock are desirable in order to obtain an efficient and homogenous cure. Although sufficient dispersion can usually be achieved with liquid curing agents, the use of such liquid agent is often inconvenient because of their instability and tendency to phase separate. While these problems can be avoided through use of solid curing agents, it is often essential to adequately subdivide and disperse such solid agents particularly when they are not appreciably soluble in the rubber stock. Exemplary solid curing agents for use with butyl rubber stock include p-benzoquinonedioxime and benzoyl peroxide on excipient bases such as calcium phosphate, flour and the like. When such curing systems are used in butyl rubber systems and heated to mild temperatures, below 50.degree. C., the butyl rubber undergoes an excessively slow cure which results in a product having a low cross-link density. Therefore, it is often desirable to use an accelerator with such solid dispersed systems.
It is an object of the present invention to provide selected quinoid/peroxide based curing systems which are capable of yielding fast cure rates at mild temperatures particularly in the presence of selected accelerators.
It is a further object of the present invention to provide a curing system capable of yielding fast cures in certain rubber stocks under mild temperature conditions. Therefore the main advantages of the utilization of the curing system of the present invention are as follows: (1) energy consumption can be minimized by effecting cure at mild instead of high temperature; (2) fast cure cycles are obtained which can translate into faster production times thus resulting in a more efficient, profitable commercial operation; and (3) the use of mild temperature curing can enable rubber parts to be produced which have physical properties which are preserved. These properties might have been adversely affected in the past when the parts were subjected to high temperature curing conditions.
It is a further object of the present invention to utilize the selected quinoid/peroxide based curing systems in the preparation of a puncture-sealing layer of puncture-sealing tires.